One of the members of the club I sometimes ride with is legally blind. He owns 5 VERY nice tandems, is a serious cyclist, and takes out classified ads in the publication of another club's newletter looking for captains. He does lots of organized rides and weekend rides with the first club I mentioned. He even went with several members of the club on a tour of Italy and several of the men in the group took turns captaining. I've heard him giving instructions to his captains during rides, schooling them in the art of tandeming .